WATERLOO, Iowa — An Iowa felon who mistakenly voted in the 2012 presidential election despite having lost his right to do so has been ordered to pay a $750 fine after pleading guilty to election misconduct.

Glen Tank of Waterloo said Friday he’s “not happy” with the way the criminal justice system handled his case from the beginning. He maintains he did nothing intentionally wrong but pleaded guilty Tuesday as part of an agreement in which he avoided prison time.

“I’ve been a nervous wreck” since the charges were filed 2 ½ years ago, he told The Associated Press. “I could’ve gone to prison. I’m not happy with the deal, but it’s the only route I could go.”

Tank owes $1,253 when mandatory surcharges and court costs are added to the fine. The auto body shop worker said he doesn’t “have that money laying around” and will have to pay in installments.

Tank, 44, said he lost his rights to vote and own firearms 12 years ago when he was convicted of third-offense operating while intoxicated. He was convicted in 2010 of illegally possessing a firearm as a felon and was on probation at the time of the November 2012 presidential election.

Tank said he believed his voting rights had been restored by then because he had been summoned for jury duty — felons cannot serve as jurors. He said he took his identification card to register at a polling place at the Waterloo police station in 2012, where a poll worker assured him that he was eligible to vote. He cast his ballot to re-elect President Barack Obama, the first time he’d voted since high school.

Tank was among 9 Waterloo felons who were charged in January 2014 as part of a state investigation into voter fraud. Five have reached plea agreements and four are scheduled to stand trial next month.

Black Hawk County officials have acknowledged that those felons had the misfortune of living near precincts where workers didn’t use electronic poll books that would have flagged them as ineligible. Felons who tried to vote elsewhere were turned away after they were identified; they weren’t charged.

“The system was not updated. It should have thrown me out,” Tank said.

Tank said he was stunned when investigators showed up to his workplace a year later asking him about the vote. While facing trial, he held out hope that the Iowa Supreme Court would restore voting rights to him and thousands of other felons. But justices ruled 4-3 in June to uphold the state’s strict ban on felon voting.